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Syncfusion Feedback

Blank PDF is generated when converting HTTPS sites to PDF in Azure

Platform: ASP.NET MVC |
Control: PDF |
Published Date: June 7, 2018 |
Last Revised Date: June 15, 2020

When converting HTTPS sites, blank paged PDF may occur due to missing of the OPENSSL assemblies in Azure website. To convert HTTPS sites, the converter requires OPENSSL assemblies. By default, some Azure websites do not have the OPENSSL assemblies. So, these assemblies should be added to the website explicitly.

Refer to the following links for prerequisites and converting HTML to PDF in Azure.



You can get the OPENSSL assemblies from the development machine, if HTTPS conversion is working on the development environment. Also, you can get the OPENSSL assemblies by installing the OPENSSL software. Please refer to the following links for more information,

OPENSSL: https://help.syncfusion.com/file-formats/pdf/convert-html-to-pdf/webkit#openssl

You can also get the OPENSSL assemblies from below link,

OPENSSL binaries: https://www.syncfusion.com/downloads/support/directtrac/general/ze/OPENSSL43076462   

Steps to overcome the blank PDF issue on Azure website:

.NET Framework:

  1. Create a new folder in a project and copy the OPENSSL assemblies to that folder.
  2. Include that folder in a project and set copy to the output directory as “Copy always”.
  3. Get the path of the OPENSSL assemblies folder in C# and set it to the environment variable. Refer to the following code snippet.
    //Set Environment variable for OpenSSL assemblies folder 
    string SSLPath = Server.MapPath("~/OpenSSL"); 
    Environment.SetEnvironmentVariable("Path", SSLPath); 


Refer to the following screenshot for more information. Screenshot for copy OPENSSL assemblies

.NET Core:

  1. Copy the OPENSSL assemblies into the QtBinariesDotNetCore folder. Refer below screenshot, Screenshot for copy assemblies into QtBinariesDotNetCore.
  2. Then set the copy to output directory as “Copy always” for all the files under QtBinariesDotNetCore folder.
  3. There is no need to set environment variable for OPENSSL, the converter can access the OPENSSL assemblies from the QtBinariesDotNetCore folder itself.

    If we set environment variable for OPENSSL in .NET core, then the conversion may get failed in Azure.



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Jordan Capa
Apr 23, 2019

thanks for the information! for the beginners and want to save time, I found zetpdf.com i heard a lot of this. I suggest it because it's the fastest pdf SKD for .NET applications.

David Jackson
Feb 11, 2021

You have to pay for this, not a good solution if you are using the Community licence

Gowthamraj Kumar [Syncfusion]
Feb 14, 2021

Hi David,

For converting HTTPS sites to PDF, the WebKit rendering engine requires OPENSSL libraries. OPENSSL libraries is a open source licensed assemblies, it is mandatory for performing HTTPS sites to PDF conversion. So, please make sure the OPENSSL assemblies are available in the machine where the conversion takes place. Please refer to the below links for more details,

If you are hosting the application in the Azure environment, By default, some Azure websites do not have the OPENSSL assemblies. So, these assemblies should be added to the website explicitly. Please refer to the below links to add OPENSSL assemblies to the Azure website.

KB: https://www.syncfusion.com/kb/8821/blank-pdf-is-generated-when-converting-https-sites-to-pdf-in-azure

If you are deploying the web application, we have to copy and paste the OpenSSL assemblies inside the QtBinaries folder for performing the HTML(HTTPS sites) to PDF conversion. So that, it will resolve the blank page issue.

Please let us know if you need any further assistance with this.


Gowthamraj K


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